477
FXUS10 KWNH 031839
PMDHMD
MODEL DIAGNOSTIC DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
237 PM EDT FRI APR 03 2020
VALID APR 03/1200 UTC THRU APR 07/0000 UTC
...SEE NOUS42 KWNO (ADMNFD) FOR THE STATUS OF THE UPPER AIR
INGEST...
12Z MODEL EVALUATION WITH PREFERENCES AND CONFIDENCE
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
..OVERALL PATTERN ACROSS THE CONUS
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: GENERAL MODEL BLEND THROUGH 05.12Z; GFS/ECMWF BLEND
AFTER
CONFIDENCE: AVERAGE
19Z UPDATE: THE REST OF THE 12Z GUIDANCE (ECMWF/UKMET/CMC) SHOWED
NO SIGNIFICANT DIFFERENCES OR DEVIATIONS FROM THE EARLIER GUIDANCE
OVER THE NEXT 3 DAYS FOR THE MASS FIELDS TO WARRANT A CHANGE IN
THE PREVIOUS BLEND PREFERENCE. FAIRLY GOOD AGREEMENT IN THE LARGE
SCALE PATTERN ACROSS THE CONUS.
---PREVIOUS DISCUSSION---
LARGE SCALE SYNOPTIC PATTERN ACROSS THE CONUS CURRENTLY FEATURES
LARGE GYRE OVER ALBERTA WHILE THE OFFSHORE NORTHEAST U.S. SYSTEM
BEGINS TO PULL AWAY. OVER THE COMING 2-3 DAYS, SEVERAL IMPULSES
WILL WORK THROUGH THAT LARGE SYSTEM OVER THE NORTHERN ROCKIES.
MEANWHILE, EASTERN PACIFIC ENERGY WILL EVOLVE INTO A LARGE CLOSED
LOW OFF THE CALIFORNIA COAST BY THE END OF THE FORECAST PERIOD.
FINALLY, WEAK SOUTHERN STREAM ENERGY WILL MOVE THROUGH THE
SOUTHERN PLAINS, TEXAS GULF COAST REGION AND BE THE FOCUS FOR
LOCALLY HEAVY RAINFALL POTENTIALLY.
OVERALL, MODELS SHOW FAIRLY GOOD AGREEMENT WITH THE 500 MB PATTERN
OVER THE NEXT 3 DAYS ACROSS THE CONUS. THIS INCLUDES THE SEVERAL
PIECES OF ENERGY ROTATING THE BASE OF THE LARGE CLOSED LOW OVER
ALBERTA. FOR THE LEADING SHORTWAVE OVER THE NORTHERN PLAINS, THE
LATEST 12Z GUIDANCE SHOWS VERY GOOD AGREEMENT.
DIFFERENCES IN THE SOUTHERN STREAM ENERGY ACROSS TEXAS ARE MORE
TIED TO MESOSCALE FEATURES AND INGREDIENTS BUT THE SIGNIFICANT
MOISTURE/INSTABILITY RETURN DOES PRESENT THE POTENTIAL FOR HEAVY
RAINFALL/FLASH FLOODING. BUT OVERALL THE 12Z MASS FIELDS ARE IN
GOOD SHAPE SUCH THAT A GENERAL MODEL BLEND IS PREFERRED.
FINALLY, OVER THE WESTERN U.S., A PAIR OF SHORTWAVES OFF THE
PACIFIC NW COAST WILL GRADUALLY EVOLVE INTO A LARGE CLOSED LOW BY
DAY 3. FOR THE INITIAL SHORTWAVE, A GENERAL MODEL BLEND IS
SUFFICIENT. AS THE SECONDARY, LARGER SHORTWAVE MOVES INTO THE AREA
AND CLOSES OFF, THERE REMAINS SOME LATITUDINAL SPREAD IN THE
LATEST GUIDANCE. OVER THE LAST SEVERAL MODEL CYCLES, THE GFS/ECMWF
REMAIN THE MORE CONSISTENT AND MIDDLE GROUND APPROACH AND FOR THIS
CYCLE, A BLEND OF THE TWO DETERMINISTIC RUNS ARE PREFERRED.
MODEL TRENDS AT WWW.WPC.NCEP.NOAA.GOV/HTML/MODEL2.SHTML
500 MB FORECASTS AT WWW.WPC.NCEP.NOAA.GOV/H5PREF/H5PREF.SHTML
TAYLOR
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